The present invention relates to an automatic loader for a stator coil lacing machine used to lace the end coils or end windings of a stator. More particularly, the present invention relates to an automatic loader for a stator coil lacing machine that lowers an arbor of the machine so that an indexing table of the automatic loader can advance a stator on the table to a position adjacent the arbor so that the arbor can be subsequently raised to position the stator on the arbor for lacing of the end coils or end windings and subsequently lowered after lacing so that the indexing table can move the laced stator away from the arbor as well as to a method for automatically loading and unloading a stator respectively on and from a stator coil lacing machine.
Stator coil lacing machines are known. These machines typically include an arbor on which a stator is positioned lie, one or mole lacing needles for stitching lacing cord around end coils or end windings of the stator, a lacing cord feeder tube for supplying lacing cold to the lacing needle, and an indexing ring for advancing the stator through an arc so that the end coils or end windings can be laced.
Some stator coil lacing machines rely on manual loading and unloading of stators on and from the arbor of the machine. Such manual loading and unloading is time consuming, repetitious, and can potentially injure an inattentive, careless operator who inadvertently contacts one or more of the needles of the machine during either loading or unloading.
Pick-and-place units for automatically loading stators onto arbors of stator coil lacing machines are known. Such pick-and-place assemblies free an operator of the machine from the task of loading and unloading, thereby allowing him or her concentrate on other activities. In addition, loading and unloading pick-and-place assemblies help protect inattentive, careless operators from possible injury resulting from contact with the lacing needles.
Current pick-and-place assemblies for stator coil lacing machines, as presently known by Applicants, load only a single stator onto the machine at any one time for lacing. Subsequent to lacing of the end coils or end windings, the laced stator is removed from the machine by the pick-and-place assembly and a new, unlaced stator then loaded on the machine for lacing.
An automatic loader for a stator coil lacing machine that increased machine output capacity by decreasing idle time required for loading and unloading of stators would be a welcome improvement. Accordingly, the present invention provides an automatic loader for a stator coil lacing machine having an arbor on which the stator is positioned to lie, one or more lacing needles for stitching lacing cord around end coils or end windings of the stator, and a lacing cord feeder tube for supplying lacing cord to the one or more lacing needles. The automatic loader includes a table on which a stator is positioned to lie. A motor of the automatic loader rotates the table to move the stator between a first position adjacent the arbor and a second position where the stator is away from the arbor. The automatic loader also includes structure for moving the arbor between a lowered position away from the stator to allow the motor to rotate the table so that the stator is above the arbor, and a raised position to allow the stator to be positioned to lie on the arbor so that the end coils or end windings of the stator can be laced. The automatic loader further includes structure for disengaging a reciprocating drive of the lacing cord feeder tube from a cam of the machine when the arbor is in the lowered position so that the reciprocating drive is drivingly reengaged with the cam when the moving structure for the arbor repositions the arbor in the raised position.
The reciprocating drive includes a cam follower coupled to a cam follower body that is drivingly joined to the lacing cord feeder tube. The cam follower is drivingly engaged with the cam when the arbor is in the raised position and disengaged from the cam when the arbor is in the lowered position.
In preferred embodiments, the disengaging structure includes a stop coupled to a base of the machine on which the cam follower body is positioned to lie when the cam follower is disengaged from the cam so that the cam follower is properly oriented to drivingly reengage the cam when the arbor moving structure repositions the arbor in the raised position. The stop may include a threaded fastener.
The lacing cord feeder tube of the machine may include an outer lacing cord feeder tube and an inner lacing cord feeder tube positioned to lie within the outer lacing cord feeder tube. In this embodiment of the machine, the reciprocating drive includes a first cam follower coupled to a first cam follower body that is drivingly joined to the outer lacing cord feeder tube and a second cam follower coupled to a second cam follower body that is drivingly joined to the inner lacing cord feeder tube. The first and second cam followers are drivingly engaged with the cam when the arbor is in the raised position and disengaged from the cam when the arbor is in the lowered position. The disengaging means for this machine embodiment includes a first stop coupled to the base of the machine on which the first cam follower body is positioned to lie when the first cam follower is disengaged from the cam and a second stop coupled to the base of the machine on which the second cam follower body is positioned to lie when the second cam follower is disengaged from the cam. The first and second stops allow the first and second cam followers to be correctly oriented to drivingly reengage the cam when the arbor moving structure repositions the arbor in the raised position. Preferred embodiments of the first and second stops include threaded fasteners.
The automatic loader further includes structure for maintaining driving engagement between a lacing needle drive of the machine and an oscillating drive of the lacing cord feeder tube when the arbor is moved between lowered and raised positions. In an embodiment of the machine, the oscillating drive includes a first crank drivingly coupled to the lacing needle drive by the driving engagement maintaining structure and a second crank drivingly coupled to the lacing cord feeder tube. The first crank includes a connecting rod having first and second ends. The first end is drivingly coupled to the lacing needle drive by the driving engagement maintaining structure and the second end is drivingly coupled to the second crank.
In preferred embodiments, the driving engagement maintaining structure includes an end block coupled to the first end of the connecting rod that is formed to include an aperture. The driving engagement maintaining structure further includes a pivot rod slidably positioned to lie within the aperture of the end block, coupled on one end to the lacing needle drive, and configured to have a length sufficient to allow the end block to travel along a portion of the length of the pivot rod as the arbor is moved between raised and lowered positions so that driving engagement between the pivot and connecting rods is maintained.
In preferred embodiments, the oscillating drive includes a key on the lacing cord feeder tube that is coupled to and drivingly engaged by the second crank. In addition, in some embodiments of the machine, the lacing cord feeder tube includes an outer lacing cord feeder tube and an inner lacing cord feeder tube positioned to lie within the outer lacing cord feeder tube. In these embodiments, the outer lacing cord feeder tube has a key that is coupled to and drivingly engaged by the second crank. The inner lacing cord feeder tube includes a key that is drivingly engaged by the outer lacing cord feeder tube.
The automatic loader further includes structure for indexing the stator through an arc when positioned to lie on the arbor so that the end coils or end windings of the stator can be laced. The indexing structure includes a rotating nest assembly on the table and a rotating nest drive assembly drivingly coupled to the nest assembly to advance the nest assembly through the arc. The rotating nest drive assembly includes structure for uncoupling a tooling index drive motor of the rotating nest drive assembly from the rotating nest assembly when the rotating motor moves the stator between the first and second positions. In preferred embodiments, the uncoupling structure includes an anti-rotation cam.
Two rotating nest assemblies may be on the table at different locations. In this embodiment, the tooling index drive motor advances only that rotating nest assembly located at the first position adjacent the arbor.
The present invention also relates to a method of loading and unloading a stator respectively on and from a stator coil lacing machine which has an arbor on which the stator is positioned to lie, a lacing needle for stitching lacing cord around coils of the stator, and a lacing cord feeder tube for supplying lacing cord to the lacing needle. The method includes the steps of moving the arbor of the machine to a lowered position, placing the stator on the table, rotating the table to a first position so that the stator is positioned to lie above the arbor, moving the arbor to a raised position so that the stator is positioned to lie adjacent the arbor, lacing the stator coils of the stator, lowering the arbor away from the stator, and rotating the table to a second position so that the stator is away from the arbor.